Improved electronic load controller and synchronizer unit for mini gird connection

The electronic load controller (ELC) has been used in the mini and micro hydro systems for balancing the power between main load and ballast load. Previously developed ELC use analog control circuits and thyristor which cut the output voltage waveform in two halves. One half is for main load and other half is for ballast load. Thus, the output voltage waveform is distorted and there is high total harmonics distortion (THD). For the interconnection of the mini and micro hydro plants to the mini gird, the total harmonics distortion created by the electronic load controllers must be reduce. This paper presents detail design of improved electronic load controller for the mini and the micro hydro systems. This improved electronic load controller is microcontroller based controller which switches binary ballast load maintaining the voltage. It reduces the total harmonics distortion meeting the grid standard. Both the detail design and experimental waveform are presented. Further, the detail design of new synchronizer unit for synchronization of the mini and micro hydro systems to the gird is also presented.